1. Field of the Invention
This invention relates to an inverted telephoto type super-wide angle lens, and more particularly to an inverted telephoto type super-wide angle lens which has a small size and a long back focal distance and well corrected aberrations.
2. Description of the Prior Art
Generally, in order to make the size of an inverted telephoto type super-wide angle lens small, the negative lens component in the front portion of the lens system is provided with a high refractive power and the lens component in the rear portion is designed to correct the aberrations of the whole lens system.
The above-described super-wide angle lens has a defect in that the rear face of the positive lens in the vicinity of the stop has a small radius of curvature convex to the image side and the convex rear face functions to greatly refract the lower half of the luminous flux incident to the lens system obliquely from a lower level. Particularly in case of a luminous flux containing light of short wavelength, a great difference appears between the refraction of the light of a short wavelength and that of the light of a standard wavelength, and accordingly, the correction for the coma and astigmatism is insufficient for the light of short wavelength. The insufficient correction of these aberrations appears on the final focal plane and accordingly the quality of the marginal portion of the image obtained is degraded.